An advanced third generation mobile communication system has introduced a concept of a default bearer in order to rapidly control various packet services and facilitate management of a service quality. Upper layer service context information for the default bearer is generated when a user equipment is firstly registered in a packet network and is always present in a terminal and a network regardless of signaling connection between the user equipment and the packet network when the user equipment is registered in the packet network.
A resource is allocated to the default bearer while the signaling connection between the user equipment and the packet network is established. When the signaling connection is cancelled, the corresponding resource is also cancelled. Since an Internet protocol (IP) signaling packet (i.e., ICMP), an IP application signaling packet (i.e., SIP), or an IP packet (i.e., E-mail) having a service quality of a ‘best-effort’ type are transmitted through the default bearer, the default bearer is the basis of the advanced third generation mobile communication system.
A procedure of establishing the default bearer is performed by being included in an attachment procedure to be executed for the user equipment to firstly access the packet network. An exceptional case may occur in which only the attachment procedure is completed while the default bearer may not normally established due to various reasons.
At this time, even if the user equipment accesses the packet network, the user equipment cannot receive an IP service, a procedure for processing the exceptional case is required.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.